Suction chest facing for paper machines and method of manufacturing the same



w. POESCHL'. .ET AL I 1,938,637

SUCTION CHEST; FACING FDR PAPER IACHINES I AND IBTHOD OF MANUFACTURING THE SAIB Filed larch 28, 1933 Patented Dec. .12, 1933 SUCTION CHEST FACING FOR PAPER MACHINES AND METHOD OF MANUFAC- TUBING THE SAME Wilhelm Poeschl, Rohrbach, and Rudolf Poeschl and Wilhelm Roth, Vienna, Austria, a'sslgnors to the firm Bohrbacher Lederfabrik Josef Poeschls Sohne A. G., Rohrbach, Austria, a corporation of Austria Application March as, 1933, Serial No. 663,150, and in Austria July 20, 1932 15 Claims.

This invention relates to suction chest facings for paper machines, that is to say those parts of such machines over which the strainers, in the form of sieves, felts, or the like, are caused to travel during the straining operation, and to methods of manufacturing the same.

It has been the usual practice hitherto to bridge over the orifice of the suction chests of paper machines for the supporting and packing of the strainers (for example sieves) by means of gratings or the like made of wood. Experience shows, however, that the continuous action of moisture coupled with'the friction set up by the traveling sieves very soon wears these wooden gratings to such an extent and in such a manner that, in the first place, a tight joint between suction chest and strainer can no longer be maintained, and consequently the suction action is diminished, and, in the second place, there is danger of damage to the valuable strainers. It thus becomes necessary for these wooden facings to be frequently worked down to a smooth surface or to be frequently renewed. i

We have now found that the above-described drawbacks can be obviated by the employment of leather for the said facings, or at least for such parts thereof as come in direct contact with the strainers; the length of life of such facings and also of the valuable strainers is very considerably increased, while, in contrast to the known wooden facings, which rapidly become rough and superficially teased, the surface of the leather facings wears smooth, so that the close and tight fit between the strainerand the facing actually improved in time.

In accordance with the invention the suction chest facings are made from leather which has preferably been impregnated, more particularly to resist moisture. The leather used is preferably treated (impregnated) with compositions of parafiln, stearine, waxes, resins, or mixtures thereof, accompanied by the application of heat, pressure, or suction action, or a combination of these measures. In this manner the leather is made "particularly well suited for the purpose in hand.

The strips obtained from the leather, if they are not as long as the breadth of the grating, are first joined together end to end, and then trimmed to the same profile throughout. In certain cases the strips thus prepared are then built up (preferably by cementing with cellulose ester solutions) until the desired cross-section is obtained.

The following method of manufacture, with the employment of specially impregnated leather, has proved highly satisfactory for the present purpose.

The leather strips, which may be taken from the length of the hide or may be shorter, are first joined together end to end, and canthen be trimmed to uniform profile. The strips thus prepared are then built up to the required crosssection by cementation with an adhesive which is insoluble in water, preferably with cellulose ester cements such as celluloid solutions. The leather strips or bars thus obtained are then trimmed precisely to the required dimensions, and in this state are then rendered waterproof by suitable impregnation, and in the course of impregnation are hardened as a protection against wear, and also to ensure the maintainance of the prescribed cross-section.

In certain cases it is advantageous not to trim the longitudinally joined leather strips at the start, but to trim to the required thickness and breadth only after these strips have been united in the above-mentioned manner in superposition, that is to say after the attainment of the full cross-section, the impregnation being carried out wholly or in part either at the commencement, on the leather material, or before trimming or after trimming, on the leather strips.

It has further proved to be particularly advantageous, in such forms of construction in which the facing consists of a single or multiple layer of leather combined with a founder tion of other material such as wood, to unite the leather to the foundation solely by means of a layer of adhesive which is insoluble in water, and preferably of cellulose ester cementing mat-, ter. In the first place a joint between the leather and its foundation which is admirably suited to withstand the constant stress to which the leather is subjected is obtained in this manner. At the same time this method of attachment rules out the possibility of the strainer ever coming into contact, through the wearing away of the leather facing, with means of attachment such as pins, screws, or the like. The leather can be practically entirely used up without any danger to the valuable strainers. Facings made of wood and leather combined in other ways will also have very considerable, advantages over. the known wooden facings. A further advantage, however, of the above-described cementing of' leather strips upon a foundation, for example of wood, is that these foundation on the paper machine.

parts can be firmly connected together in this manner without the application of pressure, since suitable pressing appliances for use on gratings of 4 to 6 metres in length are not available. In certain cases the facing in accordance with the invention can be applied in situ, by cementing the leather strips to the In this case the leather is preferably roughened before the application of the cement, and in some cases it will also be advisable to roughen the corresponding surface of the foundation.

The invention is illustrated in the accompanying drawing in which a number of examples of embodiments of the invention are shown in transverse section.

The suction chest b, which is connected to a suction pipe 0. in a known manner, and which is covered or faced at the top in the usual manner with a grating across which the strainer 11 is caused to travel, so that, as this strainer travels, surplus liquid and any air bubbles present are extracted from the portion of the belt of paper pulp situated at any one moment over the suction chest. In accordance with the present invention, and as already explained, the said grating consists entirely or partly of strips of leather.

In the constructional example shown in Fig. 1 the individual bars e of the grating c consist entirely of leather. These leather bars can consist of a plurality of combined leather strips, for example, of leather strips h, h (Fig. 4) which are horizontally superposed. Fig 5 shows a modified form in which the combined leather strips h, h are disposed onedge relatively to the surface of the strainer.

Figs. 2 and 3 show facings which are built up of leather on a wooden foundation g connected thereto.

In the form shown in Fig. 2 the facing con-' sists ofthe foundation g and a single thickness of leather 1 applied thereto.

Fig. 3 shows a facing consisting of a foundation a and of two thicknesses of leather f, f

superposed thereon. The leather facing, that is to say the leather strips, can be attached in any desired manner, and preferably replaceably, to their foundation. The attachment can also be effected by providing the strips with special profiles adapted to serve for their attachment, or to aid their attachment, to the foundation.

Figs. 6 and '7 show facing bars which are rounded off as to their surfaces adjacent the strainers, having been shaped in this manner, for example, by pressing, thus permitting of the undisturbed passage thereover of the butt joints of the strainer.

In the case of facings made up of a number of layers of leather connected together, the leather strips can be laid in any desired order or arrangement.

For suction chests of the type shown in Fig. 8, which are employed when felt strainers are used, the suction chest 2' can be provided as to its upper part with a cap 7' of leather prepared in accordance with the invention, perforations Z being provided over the suction slot is through which surplus liquid and air can be drawn through the felt m out of the paper pulp situated thereon. The portion of the perforations Z and of the slot It not covered by the felt belt strainer m is adapted to be covered by slides 11.,

for the purpose of preventing a reduction of the suction effect.

We claim:

1. A facing, more particularly for the suction chests of paper machines, characterized by the essential feature that at least such portions thereof as come into direct contact with strainers consist of leather.

2. A facing as claimed in claim 1 in which the said leather is replaceable.

3. A facing as claimed in claim 1 in which the said leather is attached to a foundation, for example of wood.

4. A facing as claimed in claim 1 in which the said leather is attached to a foundation, for example of wood, and is replaceable.

5. A facing as claimed in claim 1 in which the said leather is shaped in the manner of the known facings for the suction chambers of paper machines.

6. A facing as claimed in claim 1 in which the said portions are convex as to their upper surface.

7. A facing as claimed in claim 1 in which the upper edges of the said portions are rounded off, for the purpose specified.

8. A facing for the suction chests of paper machines comprising a leather cap adapted to cover the aperture of a suction chest, and perforations in the said cap over the said aperture, as and for the purpose specified.

9. A method of manufacturing facing elements for the suction chests of paper machines which consists in joining together end to end strips of suitably prepared leather, trimming the strips thus obtained to uniform profile, and combining a plurality of such strips, preferably by cementing, until the required cross-section is obtained.

10. A method of manufacturing facing elements for the suction chests of paper machines which consists in joining together strips of leather end to end, uniting a plurality of such strips until the required over-all thickness is obtained, by means of adhesive insoluble in water, such as cellulose ester cement, and waterproofing the same by impregnation with known agents.

11. A method of manufacturing facing elements for the suction chests of paper machines which consists in joining together strips of leather end to end, uniting a plurality of such strips until the required over-all thickness is obtained, by means of adhesive insoluble in water, such as cellulose ester cement, waterproofing the same by impregnation with known agents, and hardening the same.

12. A method as claimed in claim 9 in which the said leather strips are leveled off after the said joining together end to end of the same.

13. A method as claimed in claim 9 in which the said strips, after the said combining, are accurately trimmed to the required thickness and breadth.

14. A method as claimed in claim 10 in which the said waterproofing impregnation is carried out, at least in part, before or after the said trimming, or before the making of the said strips.

15. Facings according to any one of the preceding claims, comprising a foundation preferably of wood, and leather attached to the said foundation solely by means of cement insoluble in water, preferably cellulose ester cement.

' WILHELM POESCHL.

RUDOLF POESCHL. WILHELM ROTH. 

